Toxicity and larvicidal activity on Aedes aegypti of citronella essential oil submitted to enzymatic esterification / Toxicidade e atividade larvicida sobre Aedes aegypti de óleo essencial de citronella submetido à esterificação enzimática

The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 μg mL-¹ were obtained for the essential oil and 4.36 μg mL-¹ for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 μg mL-¹ for the essential oil of citronella and 86.30 μg mL-¹ for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.

O óleo essencial de citronela (Cymbopogon winterianus) possui diversas atividades biológicas, entre elas a ação repelente a insetos. Alguns estudos mostraram que os ésteres do ácido cinâmico podem ser aplicados como pesticidas naturais, inseticidas e fungicidas. Nesse contexto, o objetivo do presente trabalho foi avaliar a produção de ésteres a partir do óleo essencial de citronela com ácido cinâmico via esterificação enzimática. Além disso, foi investigada a toxicidade do óleo essencial antes e após a esterificação contra Artemia salina e a ação larvicida sobre Aedes aegypti. Os ésteres foram produzidos utilizando ácido cinâmico como agente acilante e óleo essencial de citronela (3: 1) em heptano e 15% em peso da enzima NS 88011 como biocatalisadores, a 70 ° C e 150 rpm. As taxas de conversão de cinamatos de citronelil e geranil foram 58,7 e 69,0% para NS 88011, respectivamente. Para a toxicidade sobre Artemia salina foram obtidos CL50 de 5,29 μg mL-¹ para o óleo essencial e 4,36 μg mL-¹ para os óleos esterificados com NS 88011. Na atividade inseticida contra larvas de Aedes aegypti, obteve-se CL50 de 111,84 μg mL-¹ para o óleo essencial de citronela e 86,30 μg mL-¹ para os óleos esterificados com a enzima NS 88011, indicando alta toxicidade dos ésteres. Os resultados demonstraram que as amostras avaliadas apresentam potencial de aplicação como bioinseticida.

Toxicity and larvicidal activity on Aedes aegypti of citronella essential oil submitted to enzymatic esterification

Abstract The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 g mL-1 were obtained for the essential oil and 4.36 g mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 g mL-1 for the essential oil of citronella and 86.30 g mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.

Resumo O óleo essencial de citronela (Cymbopogon winterianus) possui diversas atividades biológicas, entre elas a ação repelente a insetos. Alguns estudos mostraram que os ésteres do ácido cinâmico podem ser aplicados como pesticidas naturais, inseticidas e fungicidas. Nesse contexto, o objetivo do presente trabalho foi avaliar a produção de ésteres a partir do óleo essencial de citronela com ácido cinâmico via esterificação enzimática. Além disso, foi investigada a toxicidade do óleo essencial antes e após a esterificação contra Artemia salina e a ação larvicida sobre Aedes aegypti. Os ésteres foram produzidos utilizando ácido cinâmico como agente acilante e óleo essencial de citronela (3: 1) em heptano e 15% em peso da enzima NS 88011 como biocatalisadores, a 70 ° C e 150 rpm. As taxas de conversão de cinamatos de citronelil e geranil foram 58,7 e 69,0% para NS 88011, respectivamente. Para a toxicidade sobre Artemia salina foram obtidos CL50 de 5,29 g mL-1 para o óleo essencial e 4,36 g mL-1 para os óleos esterificados com NS 88011. Na atividade inseticida contra larvas de Aedes aegypti, obteve-se CL50 de 111,84 g mL-1 para o óleo essencial de citronela e 86,30 g mL-1 para os óleos esterificados com a enzima NS 88011, indicando alta toxicidade dos ésteres. Os resultados demonstraram que as amostras avaliadas apresentam potencial de aplicação como bioinseticida.

Toxicity and larvicidal activity on Aedes aegypti of citronella essential oil submitted to enzymatic esterification / Toxicidade e atividade larvicida sobre Aedes aegypti de óleo essencial de citronella submetido à esterificação enzimática

Abstract The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 μg mL-1 were obtained for the essential oil and 4.36 μg mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 μg mL-1 for the essential oil of citronella and 86.30 μg mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.

Resumo O óleo essencial de citronela (Cymbopogon winterianus) possui diversas atividades biológicas, entre elas a ação repelente a insetos. Alguns estudos mostraram que os ésteres do ácido cinâmico podem ser aplicados como pesticidas naturais, inseticidas e fungicidas. Nesse contexto, o objetivo do presente trabalho foi avaliar a produção de ésteres a partir do óleo essencial de citronela com ácido cinâmico via esterificação enzimática. Além disso, foi investigada a toxicidade do óleo essencial antes e após a esterificação contra Artemia salina e a ação larvicida sobre Aedes aegypti. Os ésteres foram produzidos utilizando ácido cinâmico como agente acilante e óleo essencial de citronela (3: 1) em heptano e 15% em peso da enzima NS 88011 como biocatalisadores, a 70 ° C e 150 rpm. As taxas de conversão de cinamatos de citronelil e geranil foram 58,7 e 69,0% para NS 88011, respectivamente. Para a toxicidade sobre Artemia salina foram obtidos CL50 de 5,29 μg mL-1 para o óleo essencial e 4,36 μg mL-1 para os óleos esterificados com NS 88011. Na atividade inseticida contra larvas de Aedes aegypti, obteve-se CL50 de 111,84 μg mL-1 para o óleo essencial de citronela e 86,30 μg mL-1 para os óleos esterificados com a enzima NS 88011, indicando alta toxicidade dos ésteres. Os resultados demonstraram que as amostras avaliadas apresentam potencial de aplicação como bioinseticida.

Research progress of miRNA involvement in plant polyphenols in regulating lipid metabolism / 中国药理学通报

Lipid metabolism disorder is an important risk factor for obesity,type 2 diabetes mellitus,non-alcoholic fatty liver disease and other chronic metabolic diseases.Micro RNAs(miRNAs)are short stranded RNA molecules with the size of 19 to 25 nucleotides that regulate lipid metabolism,within a number of physiological functions.Studies have shown that miRNAs can participate in the regulation of lipid metabolism by polyphenolic phytochemicals.In this paper,the mechanism of plant polyphenols improving lipid metabolism disorders and maintaining lipid balance through miRNA is summarized from the synthesis of triglyceride,fatty acid β oxidation,cholesterol efflux and cholesterol esterification,aiming to provide a new thought for the application and development of plant polyphenols to improve the diseases related to lipid metabolism disorders,and offer theoretical basis for the research and development of miRNA as a potential target for the prevention and treatment of diseases related to lipid metabolism disorders.

Enzymatic synthesis optimization of isoamyl butyrate from fusel oil

Many food, cosmetic and pharmaceutical industries have increased their interest in short-chain esters due to their flavor properties. From the industrial standpoint, enzyme reactions are the most economical strategy to reach green products with neither toxicity nor damage to human health. Isoamyl butyrate (pear flavor) was synthesized by isoamyl alcohol (a byproduct of alcohol production) and butyric acid with the use of the immobilized lipase Lipozyme TL IM and hexane as solvents. Reaction variables (temperature, butyric acid concentration, isoamyl alcohol:butyric acid molar ratio and enzyme concentration) were investigated in ester conversion (%), concentration (mol L-1) and productivity (mmol ester g-1 mixture . h), by applying a sequential strategy of the Fractional Factorial Design (FFD) and the Central Composite Rotatable Design (CCRD). High isoamyl butyrate conversion of 95.8% was achieved at 24 hours. At 3 hours, the highest isoamyl butyrate concentration (1.64 mol L-1) and productivity (0.19 mmol ester g-1 mixture . h) were obtained under different reaction conditions. Due to high specificity and selectivity of lipases, process parameters of this study and their interaction with the Lipozyme TL IM are fundamental to understand and optimize the system so as to achieve maximum yield to scale up. Results show that fusel oil may be recycled by the green chemistry process proposed by this study.

Fatty acid quantification method by isobutyl esterification and GC-FID/MS / 上海交通大学学报（医学版）

Objective:To establish a quantification method for understanding the varieties and concentrational changes of fatty acids under physiological and pathophysiological conditions. Methods:Based on isobutyl esterification using (-)-menthyl chloroformate and isobutanol, 27 typical fatty acids were qualitatively and quantitatively analyzed by gas chromatography-flame ionization detector/mass spectrometry (GC-FID/MS). The sensitivity and stability of the method were detected by limit of detection (LOD), limit of quantification (LOQ), and intra-day and inter-day relative standard deviation (RSD). The method was applied to four typical biological samples (human serum, urine, feces and rat liver) to verify the universality in different substrates. Results:Isobutyl esters of 27 fatty acids were effectively separated with an HP-5MS column. The results showed nice linearity within 2-3 orders of magnitude in terms of concentration with R2>0.99 for all 27 tested fatty acids. The LODs of the method were between 0.03 and 2.96 pmol on column whereas the LOQs were between 0.09 and 9.86 pmol. The results of method validation showed that the intra-day and inter-day RSDs were all under 10% in the range of high, medium and low concentrations. With this method, moreover, 10, 7, 14 and 9 fatty acids were detected in human serum, urine, feces and rat liver, respectively. Conclusion:A quantitative analytical method for fatty acids with short, media and long chains (C1-C24) is established based on isobutyl estrification in aqueous media. This method has the advantages of mild condition, high sensitivity, good stability, and simple and quick operation, and can be directly used in the detection of serum, urine, feces, liver and other biological samples, which may provide a new idea for high-throughput metabolome analysis.

A Simple and High-yield Synthesis of Hexadecyl Ferulate and Its In Vitro Antioxidant Potential

ABSTRACT Ferulic acid (FA) is a phenolic compound with well-known antioxidant potential that can be used as a promising anti-inflammatory and anti-cancer molecule. Furthermore, it has been reported to have neuroprotective activity. One of the main problems, which limit its clinical use, is its low bioavailability when administered orally. This limitation can be circumvented by changes in their structure and/or for preparing lipid-based formulations. The aim of this study was to synthesize a derivative of FA, the hexadecyl ferulate (HF). This compound would be more susceptible to pass through blood-brain barrier (BBB) due to its lipophilic character. The HF was obtained by Steglich esterification and yielded 76.77 ± 1.35%. Its structural characterization was performed by spectroscopic methods of Fourier-transformed infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). FTIR spectrum of HF presented two typical bands of ester group, a C=O ester stretching band at 1725 cm-1 and a C-O stretching band at 1159 cm-1. The 1H and 13C spectral data confirmed the chemical structure of HF. Regarding the 13C NMR spectrum, HF showed a chemical shift at δ 167.39 ppm which corresponded to the carbonyl carbon of the ester group. Concerning the in vitro antioxidant potential, HF had equivalent or improved scavenger activity than FA leading to IC50 values of 0.083 ± 0.009 nmol.mL-1 and 0.027 ± 0.002 nmol.mL-1 in DPPH radical scavenging and ABTS radical cation decolorization assays, respectively. Further studies are required in order to investigate the antioxidant effect of HF in biological media.

Synthesis of Fibrauretin Derivatives and Their Inhibition on Acetylcholinesterase Activity / 分析化学

The structure of fibrauretin made by our lab was modified. Fibrauretin was demethylated at 9-site under high temperature pyrolysis at 160℃-180℃ and was reacted with a series of acid chlorides. Twele derivatives of fibrauretin were obtained. The structure of each derivative was determined by1H-NMR and13C-NMR. The derivatives were 9-O-benzoyl-fibrauretin, 9-O-( 2-methylbenzoyl)-fibrauretin, 9-O-( 4-methylbenzoyl)-fibrauretin, 9-O-(3, 5-dimethylbenzoyl)-fibrauretin, 9-O-(4-(chloromethyl) benzoyl)-fibrauretin and other derivatives. The 12 derivatives are all new chemical compounds. Taking ATCI as substrate,the inhibitory activity on acetylcholinesterase (AChE) from the head of flies of the fibrauretin and its derivatives were screened. The results showed that most of the derivatives had improved their inhibitory activity on AChE through esterification reaction. Compounds 9-O-(4-methylbenzoyl)-fibrauretin, 9-O-(3,5-dimethylbenzoyl)-fibrauretinand 9-O-(4-(chloromethyl)benzoyl)-fibrauretin had significant inhibitory effect on AChE,and the inhibitory activity was stronger than the that of donepezil.

EVALUACIÓN DE LA PECTINA EXTRAÍDA ENZIMÁTICAMENTE A PARTIR DE LAS CÁSCARAS DEL FRUTO DE CACAO (Theobroma cacao L.)

La presente investigación tuvo como propósito evaluar el rendimiento y las características de la pectina extraída enzimáticamente a partir de la cáscara, pericarpio del fruto de cacao (Theobroma cacao L.); para ello, se realizó un diseño de tipo unifactorial, con 4 niveles de tratamiento, variando la concentración de complejo enzimático comercial Viscozyme L., de la marca Novozyme®. La pectina obtenida fue caracterizada, de acuerdo a la metodología planteada por Owens et al. 1952. Se elaboró un producto comercial tipo conserva (mermelada), donde se comparó la pectina obtenida enzimáticamente, con pectina comercial de alto y bajo metoxilo; en ambos casos fue evaluada la viscosidad aparente del fluido obtenido. Como resultados, se obtuvo mayor rendimiento de extracción de pectina promedio (13,0±0,53%), utilizando la mayor concentración de complejo enzimático (82,9 µL/100g cáscara), presentando diferencias significativas con los demás tratamientos (p<0,05); el porcentaje de metóxilo (ME) fue de 1,58±0,01%, el peso equivalente (PE) 5091,4±77,6 mg/meq; la acidez libre (AL) 0,20±0,01meq/g; el grado de esterificación (GE) 72±0,1% y el porcentaje de ácido anhídridogalacturónico (AAG) 12,5±1,0%. Con respecto al producto comercial, se observaron características reológicas de un fluido no Newtoniano pseudoplástico, con una viscosidad aparente máxima de 6043,7 mPa.s y mínima de 1741,3 mPa.s, al aumentar la fuerza del torque, presentando una menor capacidad viscosante que la pectina comercial. De acuerdo a los resultados obtenidos, se demostró que existe la oportunidad de obtener pectinas a partir de residuos del sector cacaotero, utilizando enzimas comerciales, con posibles usos en la industria alimentaria.

This research was aimed to evaluate the yield and characteristics of pectin extracted enzymatically from cocoa (Theobroma cacao L.) pod husks pericarp. For this a unifactorial type design with 4 levels of treatment varying the concentration of commercial enzyme complex Viscozyme L. of the brand Novozyme®.. The obtained pectin was characterized according to the methodology proposed by Owens et al. 1952. A commercial preserved product (jam) was elaborated, where pectin obtained enzymatically was compared with high and low methoxyl commercial pectin, in both cases the apparent viscosity of the obtained fluid was evaluated. The highest pectin extraction yield (13.0 ± 0.53%) was obtained using the highest concentration of enzyme complex (82.9 µL / 100g shell), showing significant differences with the other treatments (p <0,05). Percentage of methoxyl (ME) was 1.58 ± 0.01%, equivalent weight (PE) 5091.4 ± 77.6mg/meq, free acidity (AL) 0.20 ± 0.01meq/g, degree of Esterification (GE) 72 ± 0.1% and the percentage of anhydridogalacturonic acid (AAG) 12.5 ± 1.0%. With respect to the commercial product, rheological characteristics of a pseudoplastic non-Newtonian fluid with a maximum apparent viscosity of 6043,7 mPa.s and a minimum of 1741,3 mPa.s were observed when increasing the torque force, presenting a lower viscosity capacity than the commercial pectin. According to the results obtained it was demonstrated that there is an opportunity to obtain pectins from residues from the cocoa sector using commercial enzymes with possible uses in the food industry.

Toxicity of clove essential oil and its ester eugenyl acetate against Artemia salina / Toxicidade do óleo essencial de cravo e seu éster acetato de eugenila contra Artemia salina

Abstract The production of compounds via enzymatic esterification has great scientific and technological interest due to the several inconveniences related to acid catalysis, mainly by these systems do not fit to the concept of “green chemistry”. Besides, natural products as clove oil present compounds with excellent biological potential. Bioactives compounds are often toxic at high doses. The evaluation of lethality in a less complex animal organism can be used to a monitoring simple and rapid, helping the identification of compounds with potential insecticide activity against larvae of insect vector of diseases. In this sense, the toxicity against Artemia salina of clove essential oil and its derivative eugenyl acetate obtained by enzymatic esterification using Novozym 435 as biocatalyst was evaluated. The conversion of eugenyl acetate synthesis was 95.6%. The results about the evaluation of toxicity against the microcrustacean Artemia salina demonstrated that both oil (LC50= 0.5993 µg.mL–1) and ester (LC50= 0.1178 µg.mL–1) presented high toxic potential, being the eugenyl acetate almost 5 times more toxic than clove essential oil. The results reported here shows the potential of employing clove oil and eugenyl acetate in insecticide formulations.

Resumo A produção de compostos via esterificação enzimática possui grande interesse científico e tecnológico devido às inúmeras inconveniências relacionadas com a catálise ácida, principalmente por estes sitemas não se adequarem ao atual termo “tecnologias limpas”. Além disso, produtos naturais como o óleo de cravo, apresentam compostos com excelentes potenciais biológicos. Compostos bioativos são quase sempre tóxicos em altas doses. A avaliação da letalidade em um organismo animal menos complexo pode ser usada para um monitoramento simples e rápido, servindo também para a identificação de compostos com potencial atividade inseticida contra larvas de insetos vetores de doenças. Neste sentido, foi determinada a toxicidade frente a Artemia salina do óleo essencial de cravo e do seu derivado acetato de eugenila obtido por esterificação enzimática com lipase Novozym 435. A conversão da reação de síntese de acetato de eugenila foi de 95,6%. Os resultados referentes à avaliação da toxicidade frente ao microcrustáceo Artemia salina demonstraram que tanto o óleo (LC50= 0,5993 µg.mL–1) quanto o éster (LC50= 0,1178 µg.mL–1) apresentam elevado potencial toxicológico, sendo que o éster apresenta aproximadamente 5 vezes mais toxicidade em relação ao óleo. Estes resultados demonstram o potencial emprego do óleo de cravo e de acetato de eugenila em formulações de inseticidas.

Esterificación transesterificación de aceites residuales para obtener biodiesel / Esterificationannd transesterification of waste oils for biodiesel obtaining

El biodiesel es un biocombustible producido a partir de grasas y aceites, y debido a las desventajas del uso de los combustibles fósiles, su producción y consumo ha aumentado en los últimos años. En este trabajo fue estudiada la esterificación por catálisis ácida y la transesterificación alcalina de aceites residuales para obtener biodiesel. Las condiciones de relación aceite-metanol (6:1 y 5:1) y concentración de catalizador fueron variadas para seleccionar las más favorables para el proceso. Los aceites usados fueron recolectados en restaurantes de la ciudad de Cartagena. Se encontró que la variable con mayor efecto en el rendimiento de la reacción fue la relación aceite-metanol, favoreciéndose para bajas concentraciones de metanol (6:1), a las cuales se obtienen rendimientos superiores al 93%. La concentración de catalizador no influyó de manera significado la eficiencia de la esterificación. El biodiesel obtenido presentó buenas características de acidez y bajo contenido de azufre. Adicionalmente, se evidenció la necesidad de un pretratamiento a los aceites y una purificación del biodiesel para lograr el cumplimiento de estándares internacionales.

Biodiesel is a biofuel produced from fats and oils and because of the disadvantages of fossil oils use, its production and consumption has increased in recent years. In this work the esterification of waste oil by acid catalysis and alkaline transesterification to obtain biodiesel was studied. The oil-methanol (6:1 and 5:1) ratio conditions and catalyst concentration were varied to select the most favorable for the process. The oils used were collected in restaurants in the city of Cartagena. It was found that the variable to greater effect on the reaction yield was the oil-methanol ratio, favoring low concentrations of methanol (6:1), from which yields higher than 93% are obtained. The catalyst concentration did not affect significantly the efficiency of esterification. The biodiesel obtained had good acidity characteristics and low sulfur content. Additionally the need for a pretreatment to oils and biodiesel purification to achieve compliance of international standards was evidenced.

Direct preparation of fatty acid methyl esters and determination of in vitro antioxidant potential of lipid from fresh Sebal causarium Seed.

Classical method of sample preparation for fatty acid analysis is a complicated, rigorous, multiple-step process that is often time-consuming. However, innovation has made it possible to obtain fatty acids esters in a single step without compromise of the quality and quantity of the products obtained. Fatty acid methyl esters (FAMEs) were obtained from Sabal causiarum seed using direct trans-esterification method. The reaction was performed in a one necked glass reactor equipped with a reflux condenser. The composition of the FAMEs obtained was analyzed using GC-FID/GC-MS. The FAMEs was also evaluated for its antioxidant potential using DPPH assay while α- tocopherol served as a standard. From the Total ion chromatogram, a total of twelve fatty acids were identified with the dominant being linoleic acid (29.83%), an essential polyunsaturated omega-6 fatty acid. Other compounds obtained in significant yield include palmitic acid (20.75 %), dodecanoic acid (12.15 %), oleic acid, an omega-9 monounsaturated fatty acid (11.51%), 11-Octadecenoic acid (5.89 %), Ceric acid (4.97) and lignoceric acid (4.56 %). The oil had higher antioxidant potential (with IC50 value 0.19 ± 0.31 mg/mL) than the standard, alpha-tocopherol (with IC50 of 0.25 ± 0.4 (mg/mL). The direct trans-esterification method enables the quick determination of the fatty acid profile of Sabal causiarum seed. It is a viable method that saves time, limit use of solvents and reduce the possibility of contaminations that is associated with classical multistage procedure. The chemical composition and high antioxidant value of the oil is a strong indication of the future economical and biological relevance of the Sabal causiarum seed oil.

Synthesis of Aryl-pyridazinone Acid and Curcumin Ester / 中国药房

OBJECTIVE:To synthesize the aryl-pyridazinone acid and curcumin ester. METHODS:With the raw material of 5-methyl-2-(3-chloro-4-fluorophenyl)-2-oxo-pyridazine acid (compound 1) and curcumin,there was ester-forming in the two sides of a phenolic hydroxyl and pyridazin-6-one carboxyl in curcumin by the catalysis of N,N-dicyclohexyl carbodiimide(DCC)/4- dimethylaminopyridine (DMAP). The targeted product,MS and NMR characterization of the structure were obtained through column chromatographic separation. Single factor was adopted to detect the effect of mixture ratio of curcumin and compound 1,re-action temperature and time and catalyst on the reactions. RESULTS:The productivity of targeted product (aryl-pyridazinone acid and curcumin ester)was 56.3%(in curcumin),the content by HPLC was 98.1%. The optimum conditions were as follows as the mixture ratio of curcumin and compound 1 was 1∶3,reaction temperature was 50 ℃,reaction time was 10 h and the catalyst was DCC/DMAP. CONCLUSIONS:The aryl-pyridazinone acid and curcumin ester is successfully synthesized with stable process.

Production and characterization of an extracellular lipase from Candida guilliermondii

Extracellular lipases from the endophytic yeast Candida guilliermondii isolated from castor leaves (Ricinus communis L.) were produced using low-cost raw materials such as agro-industrial residues and applying them in the esterification of oleic acid for evaluating their potential use in biodiesel production. After partial purification using ammonium sulfate, the enzyme was characterized and presented higher activity (26.8 ± 1.5 U mL-1) in the presence of 5 mmol L-1 NaCl at 30 ºC and pH 6.5. The production through submerged fermentation was formerly performed in 150 mL erlenmeyer flasks and, once the enzyme production was verified, assays in a 14 L bioreactor were conducted, obtaining 18 ± 1.4 U mL-1. The produced enzyme was applied in the oleic acid esterification under different solvents: hexane, cyclohexane or cyclohexanone) and different acid:alcohol molar ratios. Higher ester conversion rate (81%) was obtained using hexane and the molar ratio of 1:9 was the best conditions using methanol. The results suggest the potential for development of endophytic yeast in the production of biocatalyst through submerged fermentation using agroindustrial residues as culture medium.

Kinetic constraints and features imposed by the immobilization of enzymes onto solid matrices: A key to advanced biotransformation.

The kinetics of immobilized enzymes can not be analyzed by means of the simple Michaelis-Menten concept, which generally fails to describe the immobilized state due to both its probable barriers, and because the active concentration of the enzyme approaches, or even exceeds this of its substrate(s). In such cases, the various experimental data are usually treated by complex rate equations comprising too many parameters acquiring different natures and meanings, depending on both the properties of the immobilization state and the experimental conditions; thus, more likely, only apparent values of the Michaelis-Menten kinetic parameters can be estimated experimentally. Likewise, immobilization is often a key method in optimizing the operational performance of enzymes, in both laboratory and industrial scale, and affects considerably the kinetics in non-aqueous and non-conventional media due to several issues as the structural changes of the enzyme molecule, the heterogeneity of the system, and the partial or total absence of water. In this work a theoretical approach is described on the formulation of simplified rate equations, reflecting also the actual mass balances of the reactants, in the case where esterification synthetic reactions are catalyzed by immobilized lipases, in either a non-aqueous organic solvent or in a non-solvent system.

Modeling and optimization of lipase-catalyzed synthesis of cholesteryol vinyl hemi-sebacate by response surface methodology / 中国药学杂志

OBJECTIVE: To model and optimize the reaction conditions of enzymatic esterification of cholesterol with diethenyl decanedioate in isooctane by response surface metodology (RSM).

Study of reaction parameters and kinetics of esterification of lauric acid with butanol by immobilized Candida antarctica lipase.

Esterification of lauric acid with n-butanol, catalyzed by immobilized Candida antarctica lipase (CAL) in aqueous-organic biphasic solvent system was studied. Effects of various reaction parameters on esterification were investigated, such as type and amount of solvent, amount of buffer, pH, temperature, speed of agitation, amount of enzyme, butanol and lauric acid. The most suitable reaction conditions for esterification were observed at 50ºC and pH 7.0 using 5000 μmoles of lauric acid, 7000 μmoles of butanol, 0.25 ml phosphate buffer, 1 ml of isooctane as the solvent and 50 mg of immobilized enzyme in the reaction medium at agitation speed of 150 rpm. Maximum esterification of 96.36% was acheived in 600 min of reaction time at n-butanol to lauric acid molar ratio of 1: 0.7. Kinetic study for the esterification of lauric acid with n-butanol using immobilized CAL was carried out and the kinetic constants were estimated by using non-linear regression method. The estimated value of Michaelis kinetic constants for butanol (KmBt) and acid (KmAc) were 451.56 (M) and 4.7 × 10-7(M), respectively and the value of dissociation constant (KBt) of the butanol-lipase complex was 9.41 × 107(M). The estimated constants agreed fairly well with literature data.

Protection of phosphate esterification polysaccharides from Tremella fuciformis on hematopoietic function in radiation-injured mice / 中草药

Objective: To study the effect of phosphate esterification polysaccharides from Tremella fuciformis (PEPTF) on hematopoietic function in radiation-injured mice. Methods: Rats were randomly divided into six groups: control, model, polysaccharides from T. fuciformis (10 mg/kg) positive control, low-, mid-, and high-PEPTF (10, 30, and 60 mg/kg) groups. Before irradiated with 137Cs γ-ray, rats were ip administered once daily for 3 d. On the day 7 after irradiation, the rats were sacrificed. Colony-forming unit of spleen, number of nucleated cells in bone marrow, number of white blood cells, spleen index, and thymus index were used as observation indexes to investigate the effect of PEPTF on hematopoietic function of mice. Results: Compared with the model group, the number of the nucleated cells in bone marrow, the number of white blood cells, spleen index, and thymus index of mice increased markedly. Conclusion: PEPTF have the protective effect on the hematopoietic function of radiation-injured mice.

The study on relationship of fractional esterification rate of high density lipoprotein cholesterol and coronary artery disease / 重庆医学

Objective To assess the relationship between fractional esterification rate of high density lipoprotein cholesterol (FERHDL) and coronary artery disease .Methods The patients were underwent coronary angiography in this hospital in the last three years were collected ,according to the results of coronary angiography ,286 patients were divided into CHD group(n=196) and non-CHD group(control group ,n=90) .And according to the number of pathological coronary artery ,the patients with coronary heart disease were divided into single-vessel subgroup(n=73) ,double vessel lesion subgroup(n=72) ,three branch lesions subgroup (n=51) .The relationship between FERHDL and coronary artery disease were analyzed .Results The FERHDL of CHD group was significantly higher than that in the control group ,the difference was statistically significant (P<0 .05) .It was a tendency that the FERHDL increased with coronary lesions increasing (P<0 .05) .The FERHDL was significant independent correlated with the low density lipoprotein cholesterol b-C(LDLb-C) ,triglycerides(TG) ,high density lipoprotein cholesterol 2-C(HDL2-C) ,high density lipoprotein cholesterol C(HDL-C) .FERHDL was positively correlated with LDLb-C(r=8 .473 ,P=0 .000) ,TG(r=0 .714 ,P=0 .002) and negatively correlated with HDL2-C(r= -0 .692 ,P=0 .024)、HDL-C(r= -0 .829 ,P=0 .008) .Conclusion The value of FERHDL was significantly increased in CHD patients and correlated with the aggravation severity of the CHD .The change of FERHDL was significant correlated with particle size of HDL and LDL particle size .

Kinetic analysis of batch ethanol acetylation in isothermal non-stationary multiphase systems by lyophilized mycelium of Aspergillus oryzae

A relatively complex network of reactions has been investigated, using as a network model the isothermal batch esterification of acetic acid with ethanol in n-heptane catalyzed by lyophilized mycelium of Aspergillus oryzae. The kinetic analysis was firstly carried out on the whole system, without any simplification, by means of the well-known integral method. Owing to the poor results obtained by this way, we developed an alternative approach, combining initial rates and integral analysis and reducing the number of empirical parameters to be determined by the use of equilibrium data. All the values of the parameters calculated according to this "composite" approach to kinetic analysis well correlate with experimental data.